Simplify the following expression: ${-8x-8-1-7x}$
Explanation: Rewrite the expression to group the ${x}$ terms and numeric terms: $ {-8x - 7x} {-8 - 1}$ Combine the ${x}$ terms: $ {-15x} {-8 - 1}$ Combine the numeric terms: $ {-15x} {-9}$ The simplified expression is $-15x-9$